Garden Pests & Diseases


Protect Your Garden Naturally

Your garden center offers lots of safe, nontoxic products for use in repelling and eradicating insects, pests and disease that threaten your gardens. Barriers such as netting and row covers protect plants from flying insects as well as from deer and other hungry mammals. Copper tape can be used to protect trees and plants from slugs and snails. Bacillius thuringienses, or B.t., is a bacterium that kills leaf-eating caterpillars by invading their digestive system. B.t. is sold in both powder and liquid forms under a number of trade names including Dipel, Condor and Biotrol. Other bacterial controls available include Milky Spore Disease (Bacillus popillae) for use against Japanese Beetle grubs.

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Good Bugs vs Bad Bugs

Releasing large numbers of Lady Bugs or Praying Mantis into areas of your garden infested with insect pests is lots of fun and can be a very effective means of controlling aphids, mealy bugs, leaf worms, and many other pests. Lady Bugs should be released at night near the base of infested plants where they will seek out and devour insect pests. Praying mantids are voracious predators that will feed on many of the larger insect pests including grubs, beetles, leafhoppers and caterpillars. These beneficial insects are available for sale at garden centers and through mail order.

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Pest Control

Now that our vegetables and flowers are planted and thriving, it’s prime time for the hoards of insect pests and diseases to invade our little piece of paradise. Here are a few tips to help you through this scary attack.

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Garlic & Pepper Spray

Protect your garden plants from cabbageworms, caterpillars, hornworms, aphids, flea beetles and other chewing/sucking insects by routinely using a natural spray that you can make at home. The spray must be applied regularly, especially after a rainfall. Brew up a batch as follows:

6 cloves of garlic
1 Tbsp dried hot pepper
1 minced onion
tsp pure soap (not detergent)
1 gallon hot water

Blend & let sit for 1 - 2 days. Strain & use as spray. Ground cayenne or red hot pepper can also be sprinkled on the leaves of plants (apply when leaves are slightly damp) to repel chewing insects or added to the planting hole with bone meal or fertilizer to keep squirrels, chipmunks, dogs and other mammals away from your gardens. Be sure to reapply after rain.

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Bad Bugs Keep Out!

Here are some safe and easy steps you can take to reduce insect damage to your garden. To prevent cutworm attacks, place a newspaper or cardboard collar around the stems of tender transplants at the soil surface. Crop rotation and good garden sanitation is essential to repelling squash bugs and cucumber beetles. Heavy mulching can help prevent potato and cucumber beetle larvae from finding the plants. Row covers are another effective barrier against insects, though they may need to be removed to allow pollination to occur. Interplanting crops with aromatic plants like garlic, chives, or marigolds can repel many problem insects. Soap and water, garlic, and hot pepper sprays can easily be prepared at home for use against many pesky garden insects. The best solution to pest problems, however, is maintaining sound garden practices like building healthy soil, rotating crops, and cleaning up your garden at the end of the season.

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Simple, Safe Sprays for Controlling Insect Pests

  • For some pests like aphids and caterpillars, a strong spray from a garden hose can knock them loose. It’s important to spray the underside of the leaves where most insect pests reside.
  • Bt (Bacillus thuringiensis) is a bacterial disease that is safe to humans but wreaks havoc on many caterpillar and larval stage pests including Colorado potato beetle, cabbage looper, and tomato hornworm. It is sold in the form of a soluble powder that is sprayed on the plant surface and is then ingested by the pest. Be sure to use the right type of Bt for the pest you want to control.
  • Homemade sprays are easy to make and use but must be applied regularly. Mix one tablespoon of dishwashing liquid per ½ gallon of water and spray insect pests directly to kill. It is best to spray plants on cloudy days or in the early evening when they are not in direct sunlight. It’s a good idea to rinse the soap residue off after a couple of hours to reduce leaf damage to sensitive plants. You can prepare garlic and hot pepper sprays to prevent insect pests from munching on plants. Mix several garlic cloves with water and steep overnight. Strain and spray on plants every few days or after rainfall. You can do the same using hot peppers in place of or in addition to the garlic. These bad tasting sprays can also deter small mammals.

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Control of Black Spot & Powdery Mildew

Powdery mildew is a fungal disease that affects beans, cucumbers, melons, peas, pumpkins, squash and strawberries as well as many fruit trees and roses. Black spot is a fungal disease that produces black spots on the leaves of infected roses. In severe cases, the plant can be defoliated. To remedy these problems, mix 3 Tbs Baking Soda, 2½ Tbs horticultural oil and one gallon of water. Spray the mix onto infected plants. Reapply as often as needed.

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Deer Deterring Tips

  • Mix one egg per gallon of water and spray on plants. Reapply once a week or after rain.
  • Tie unused fabric softener sheets onto trees and shrubs or on stakes around plants being bothered by deer. They seem to hate the smell, so buy the brand with the strongest scent and only replace if the scent has faded. Rain does not seem to hinder their effectiveness.

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Invasion of the Flea Beetles!!!

These tiny black jumping beetles are everywhere this season chewing lots of small, round holes in the leaves of most veggies. The adult beetle can transmit viral and bacterial diseases to some crops and can kill small seedlings. Their larvae attack plant roots weakening the plant. Flea beetles overwinter as adults and emerge very early in spring ready to eat. Use row covers or horticultural cloth as a barrier to keep the beetles off your early crops. As the plants grow larger, simply cover the top to shade them a bit. Flea beetles don’t take kindly to shade. Homemade sprays using garlic or hot pepper will repel flea beetles if used regularly. Interplanting tomatoes with plants in the cabbage family (like collards) will also help to reduce flea beetle populations.

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